Multi-chamber pump apparatus, systems, and methods

ABSTRACT

Disclosed are apparatus adapted to dispense and/or aspirate liquids, such as in a clinical analyzer. In one aspect, a multi-chamber pump apparatus is disclosed that has a pump body containing first and second chambers, a piston having a first piston portion of a first pump area A1 received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber, and an actuator coupled to the piston. The first and second chambers can be selectively accessed to improve metering accuracy at dissimilar flow volumes from the chambers. Methods and systems including the multi-chamber pump apparatus are provided, as are other aspects.

FIELD

The present invention relates generally to apparatus, systems, andmethods adapted to aspirate and dispense liquids.

BACKGROUND

In automated medical specimen testing, biological fluid specimens,reagents, wash liquids, and purified water may be aspirated and/ordispensed for various purposes. For example, in some automated testingsystems (e.g., clinical analyzer instruments), biological fluidspecimens (e.g., blood, blood plasma, interstitial fluid, spinal fluid,urine, or the like) contained in sample containers (such as test tubes,sample cups, vials, cuvettes, and the like) may be tested to determine apresence of an analyte, other identifiable substance, or acharacteristic thereof. As part of this process, metering (pumping) ofthe biological fluid, reagent, and/or purified water may be desired. Inorder to provide for testing accuracy, the metering of such fluidsshould, in some instances, be very precise.

For example, in some testing methods, such as the so-called “chasemethod,” a relatively smaller volume of biological fluid is firstaspirated and dispensed by a metering apparatus, and the dispensing ofthis biological fluid is followed (chased) by dispensing a relativelylarger volume of purified water. In the chase method, the volume ofdispensed process fluid may be greater than the volume of the biologicalfluid that is dispensed. In a so-called “neat method,” a small amount ofbiological fluid is aspirated and dispensed (on the order of 1-3 μL). Inthe neat method, the purified water may only be the transport vehicle(i.e., a liquid backing in the conduit) that allows for the metering ofthe biological fluid, even though the purified water may not itself bedispensed. In other words, the purified water acts as the backing thatenabling the aspiration and dispensing of the biological fluid. However,for both methods, it should be understood that inaccurate metering maylead to less accurate specimen testing results.

Additionally, as part of washing probes, sometimes relatively largervolumes of water (e.g. purified water) may be dispensed. This may bedispensed by a probe or into a receptacle (e.g., washing/drain system)that is used to wash the probe. Wash liquid containing detergents mayalso be dispensed.

In prior art systems, separate pumps have been utilized to accomplishprecise metering at both relatively lower volumes and the relativelylarger volumes. Accordingly, apparatus, systems, and methods that mayimprove fluid dispensing/aspiration are desired.

SUMMARY

According to a first aspect, a multi-chamber pump apparatus is provided.The multi-chamber pump apparatus includes a pump body containing a firstchamber and a second chamber, each adapted to contain a liquid, a pistonhaving a first piston portion of a first pump area A1 received in thefirst chamber, and a second piston portion of a second pumping area A2received in the second chamber, and an actuator coupled to the piston.

In a system aspect, a liquid delivery system is provided. The liquiddelivery system includes at least one liquid source, a multi-chamberpump apparatus fluidly coupled to the at least one liquid source, themulti-chamber pump apparatus having a pump body with a first chamber anda second chamber, a piston having a first piston portion of a first pumparea A1 received in the first chamber, and a second piston portion of asecond pumping area A2 received in the second chamber, a dispensingand/or aspirating device fluidly coupled to a first chamber outlet ofthe first chamber, and a second chamber outlet of the second chamber, afirst flow-controllable passage fluidly coupled to the first chamber;and a second flow-controllable passage fluidly coupled to the secondchamber.

In a method aspect, an improved liquid delivery method is provided. Themethod includes providing at least one liquid source containing aliquid, providing a multi-chamber pump apparatus fluidly coupled to theat least one liquid source, the multi-chamber pump apparatus having apump body with a first chamber and a second chamber, a piston having afirst piston portion of a first pump area A1 received in the firstchamber, and a second piston portion of a second pumping area A2received in the second chamber, providing a dispensing and/or aspiratingdevice fluidly coupled to a first chamber outlet of the first chamber,and a second chamber outlet of the second chamber, and translating thepiston to pump liquid to the dispensing and/or aspirating device.

Still other aspects, features, and advantages of the present inventionmay be readily apparent from the following detailed description byillustrating a number of exemplary embodiments and implementations,including the best mode contemplated for carrying out the presentinvention. The present invention may also be capable of other anddifferent embodiments, and its several details may be modified invarious respects, all without departing from the scope of the presentinvention. Accordingly, the drawings and descriptions are to be regardedas illustrative in nature, and not as restrictive. The drawings are notnecessarily drawn to scale. The invention is to cover all modifications,equivalents, and alternatives falling within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an isometric view of an example liquid meteringsystem according to the Prior Art.

FIG. 2A illustrates an isometric view of a multi-chamber pump apparatusaccording to embodiments.

FIG. 2B illustrates a cross-sectioned side view of a multi-chamber pumpapparatus according to embodiments.

FIG. 2C illustrates an end view of a first piston portion (shownhatched) of a multi-chamber pump apparatus according to embodiments.

FIG. 2D illustrates an end view of a second piston portion (shownhatched) of a multi-chamber pump apparatus according to embodiments.

FIG. 2E illustrates an isometric view of a piston of a multi-chamberpump apparatus according to embodiments.

FIG. 2F illustrates an isometric view of a coupling of a multi-chamberpump apparatus according to embodiments.

FIG. 2G illustrates an isometric view of a lower pump housing of amulti-chamber pump apparatus according to embodiments.

FIG. 2E illustrates an isometric view of a middle pump housing of amulti-chamber pump apparatus according to embodiments.

FIG. 2I illustrates an isometric view of an upper pump housing of amulti-chamber pump apparatus according to embodiments.

FIG. 2J illustrates an isometric view of a pump motor of a multi-chamberpump apparatus according to embodiments.

FIG. 2K illustrates an isometric view of a sensor of a multi-chamberpump apparatus according to embodiments.

FIG. 3A illustrates a block diagram view of a liquid dispensing systemincluding a multi-chamber pump apparatus according to embodiments.

FIG. 3B illustrates a block diagram view of another liquid dispensingsystem including the multi-chamber pump apparatus according toembodiments.

FIG. 3C illustrates a block diagram view of another liquid dispensingsystem including the multi-chamber pump apparatus according toembodiments.

FIG. 4 is a flowchart illustrating a liquid delivery method of accordingto embodiments

DETAILED DESCRIPTION

In current liquid dispensing and aspirating systems, achieving precisionin the metering of both a relatively large volumes of fluid such as inthe “chase” method, and relative low volumes of fluid such as in the“neat” method, provides a significant challenge. This is because pumps,in general, become inefficient and quite inaccurate when dispensingfluid at less than about 20% of their intended stroke. In order toprovide sufficient accuracy for both relatively high volume aspirationand/or dispense operations and also for relatively low volume aspirationand/or dispense operations, multiple pumps are used in prior artsystems. In particular, one pump may be designed to obtain accuracy forthe relatively lower dispense/aspirate volumes, and the other isdesigned to achieve accuracy at relatively higher volumedispense/aspiration volumes. However, utilizing multiple pumps mayresult in unwanted system expense and complexity.

As shown in FIG. 1, a prior art liquid dispense/aspiration system 100 isshown. The system 100 includes a feed tank 102, which provides a supplyof liquid, such as purified water or saline buffer, for example, to afluid metering apparatus 104 including a first metering pump 106, asecond metering pump 108, valves 110, a distribution manifold 112, adelivery line 114, and a probe 116. The metering line 114 fluidlycouples the probe 116 to the metering apparatus 104 and allows bothaspirating and dispensing of liquids. The feed tank 102 may be filleddirectly from a purification system (not shown), which receives itsinflow of water directly from a water supply (not shown).

Accordingly, an improved system and pump capable of achieving bothrelatively precise high volume aspiration and/or dispense operations,and relatively precise low volume aspiration and/or dispense operationsis desired. To solve the above-identified problems, a multi-chamber pumpapparatus is provided. In some instances, such as those where themetered volume of the fluid is relatively small (such as in theabove-mentioned “neat” method), the pump may dispense and/or aspirateutilizing a first chamber, whereas for relatively larger dispense and/oraspiration operations, a second chamber may be used. A single drivemotor may be used to drive a piston operable in both the first andsecond chambers.

These and other aspects and features of the invention will be describedwith reference to FIGS. 2A-4 herein.

In accordance with a first embodiment of the invention, as best shown inFIG. 2A-2B, a multi-chamber pump apparatus 200 is described. Themulti-chamber pump apparatus 200 may be coupled to, or be part of, aliquid metering system 300A-300C of an instrument as is shown in FIG. 3Athrough FIG. 3C, for example. The instrument may be a clinical analyzeror other instrument adapted to aspirate and/or dispense biologicalfluids, reagents and/or other liquids as part of testing the biologicalfluids. The multi-chamber pump apparatus 200 may be provided in othersystems in which precisely-controlled liquid aspiration and/or dispenseoperations are carried out.

The multi-chamber pump apparatus 200 comprises a pump body 220 having afirst chamber 222 and a second chamber 224, each adapted to contain aliquid to be aspirated or dispensed. The liquid may be biological fluid,reagent, water (e.g., purified water), wash solution, liquid detergent,or the like. The multi-chamber pump apparatus 200 also includes a piston226 (See FIG. 2E). The piston 226 is a translating member thattranslates within the pump body 220 and has a first piston portion 226Lof a first diameter D1 (FIG. 2E) and a first pumping area A1 (FIG.2C—shown hatched) received in the first chamber 222, and a second pistonportion 226U of a second diameter D2 (FIG. 2E) and a second pumping areaA2 (FIG. 2D—shown hatched) received in the second chamber 224.Generally, the piston 226 may include concentric cylinders, whereinD1>D2.

In the depicted embodiment, the first pumping area A1 is an annulus,whereas the second pumping area A2 is a circle. In the depictedembodiment, D1>D2. The first diameter D1 may be between about 0.188 in(4.78 mm) and about 1.50 in (38.1 mm), and about 0.403 in (10.2 mm) inthe depicted embodiment. The first pumping area A1 may be between about0.0023 in² (1.484 mm²) and about 1.735 in² (1119.0 mm²) and about 0.017in² (11.0 mm²) in the depicted embodiment. The second diameter D2 may bebetween about 0.180 in (4.57 mm) and about 2.00 in (50.8 mm), and about0.375 in (8.89 mm) for the depicted embodiment. The second pumping areaA2 may be between about 0.025 in² (16.4 mm²) and about 3.14 in² (2030mm²), and about 0.110 in² (71.2 mm²) in the depicted embodiment. Inparticular, A2>A1, and in some embodiments A2≧3A1, and in someembodiments A2≧5A1, and even in some embodiments A2≧8A1. The pistonportions 226U, 226L may be formed as part of a stepped-diameter piston226 including a first shaft sealing portion 227L and a second shaftsealing portion 227U that seal with lower and upper seals 227SL, 227SU,respectively. The first shaft sealing portion 227L and a second shaftsealing portion 227U may be co-axial. In some embodiments, the piston226 may be a precision-ground ceramic material, such as 95% zirconia.Other materials may be used.

The multi-chamber pump apparatus 200 includes an actuator 228 coupled tothe piston 226. The actuator 228 may be a stepper motor such as shown inFIG. 2J, whereas rotation of the stepper motor results in precise linearmotion of a shaft 228S of the actuator 228, and, thus, translationalmotion of the piston portions 227U, 227L in first and second chambers222, 224. Optionally, the actuator 228 may be a pneumatic actuator,servo-actuator, or the like. Other suitable motors to impart linearmotion may be used.

The actuator 228 may be coupled to the piston 226 by any suitable means,such as a coupling 230. Any suitable coupling 230 may be used. Forexample, the piston 226 may be attached to the coupling 230 by beingadhesively bonded an end thereof into a pocket 230P formed in thecoupling (See FIG. 2F). The shaft 228S of the actuator 228 may beattached to the coupling 230 by a suitable fastener 232, such as a setscrew, received in a threaded hole 233 (FIG. 2F) or other suitablemechanical connection. The coupling 230 may have a flag 230F extendingfrom a mean body of the coupling 230 that is configured and adapted tointerface with a sensor 234. The sensor 234 may be mounted to the pumpbody 220 such as by screws or the like, and the flag 230F may beconfigured to interact with the sensor 234 to provide informationconcerning an axial position of the piston 226 along its stroke.

The sensor 234 may be any suitable type of sensor, for example. Thesensor 234 may sense an uppermost axial dispense excursion of the piston226 of the pump apparatus 200. For example, the sensor 234 may be alight sensor having a light beam that when broken produces a changedsignal output. The interaction with the sensor 234 may involve the lightbeam being broken by the flag 230F passing between a light generator anda light receiver housed in legs 234A, 234B of the sensor 234 (See FIG.2K). The breaking of the light beam may signify that a maximum dispenselocation of the pump 100 has been reached. Optionally, other locationsmay be signified, such as bottom-most stroke location, or a mid-strokelocation.

The actuator 228 may be mounted to a lower housing 236 of the pump body220 by suitable fasteners 238 such as socket head cap screws or the likethat may be received through flanges 236F (FIG. 2G) at a lower end ofthe lower housing 236. Other fastening means may be used. Lower housing236 may include a recess 236R that receives the actuator shaft 228S,coupling 230, and a sensing portion of the sensor 234. The sensor 234may be mounted to the lower housing 236 and access the flag 230F througha hole 236E (FIG. 2G) formed through a sidewall of the lower housing236.

Coupled to the lower housing 236 at an upper end thereof may be a middlehousing 240 (see also FIG. 2E). The middle housing 240 may include thefirst chamber 222 and the shaft seals 227SL, 227SU at a lower and upperend thereof. The middle housing 240 may also include a first chamberinlet 242I, and a first chamber outlet 242O to and from the firstchamber 222, respectively. The first chamber inlet 242I is adapted tofluidly couple to a liquid source such as by a conduit, and the firstchamber outlet 242O is adapted to fluidly couple to a dispensing and/oraspirating device such as a probe or liquid receptacle (See FIGS. 3A-3C)also by a conduit or a flow-controllable passage. The piston 226, in thedepicted embodiment, extends through the middle housing 240 and theshaft seals 227SL, 227SU seal against the shaft sealing portions 227L,227U. The shaft seals 227SL, 227SU may each be a spring energized U-Cupreciprocating type seals, for example. Other suitable dynamic seals maybe used.

Coupled to the middle housing 240 may be an upper housing 244 (See alsoFIG. 2I). Upper housing 244 may include the second chamber 224 and thesecond piston portion 227U. The upper housing 244 may also include asecond chamber inlet 246I, and a second chamber outlet 246O to and fromthe second chamber 224, respectively. The second chamber inlet 246I isadapted to fluidly couple to a liquid source such as by a conduit, andthe second chamber outlet 246O is adapted to fluidly couple to adispensing and/or aspirating device such as a probe or liquid receptacle(See FIGS. 3A-3C) also by a conduit or a flow-controllable passage. Thevarious inlets and outlets, 242I, 242O, 246I, 246O may be angled toallow bubbles to easily be dislodged during a bleeding process thereof.

Each of the middle housing 240 and the upper housing 244 may bemanufactured from a transparent material, such as an acrylic plasticsuch that any bubbles therein may be seen and removed. The shaft seals227SL, 227SU may include a housing seal that functions to seal betweenthe middle housing 240 and the upper housing 244, and the middle housing240 and the lower housing 236 to seal gaps there between. The upperhousing 244 and middle housing 240 may be coupled to the lower housing236 with common fasteners 247 (e.g., bolts) passing through apertures248 in the upper housing 244 and apertures 249 in the middle housing 240and threading into threaded holes 250 in the lower housing 236 (FIG.2G). Other fastening means may be employed.

Now referring to FIGS. 3A-3C, several embodiments of liquid deliverysystems 300A-300C are shown. The liquid delivery systems 300A-300C maybe included in an instrument, such as a clinical analyzer and areconfigured and adapted to deliver one or more liquids to one or moredevices. Each of the liquid delivery systems 300A-300C includes at leastone liquid source, such as first liquid source 318. Some embodiments mayinclude more than one liquid source such as first liquid source 318 andsecond liquid source 319. The one or more liquid sources (e.g., 318 or318 and 319) may be fluidly coupled to the multi-chamber pump apparatus200. The multi-chamber pump apparatus 200 may be as described herein.

In particular, the one or more liquid sources (e.g., 318 or 318 and 319)may be fluidly coupled to the respective first chamber inlet 242I andsecond chamber inlet 246I of the multi-chamber pump apparatus 200. Thefluid coupling may be provided by any suitable passage, such as one ormore liquid-carrying conduits 321, for example. On an output side, therespective first chamber outlet 242O and second chamber outlet 246O ofthe multi-chamber pump apparatus 200 are fluidly coupled to a dispensingand/or aspirating device 325. The fluid coupling on the output side ofthe multi-chamber pump 200 may be provided by any suitable passage, suchas a flow-controllable passage comprising one or more conduits 321 andone or more valves 323, for example. A suitable controller 327 may beprovided to carry out the dispensing and/or aspirating by themulti-chamber pump 200.

The various liquid sources 318, 319 may need to be replenished from timeto time. Such replenishment may be by manual refilling, or automaticrefill as dictated by a level sensor (e.g., a float type sensor)situated at an appropriate level in a tank, the valve (not shown) may beopened and a fresh supply of liquid may be allowed to enter. Forexample, the liquid sources 318, 319 may be purified water, salinebuffer solution, concentrated reagent, detergent, wash liquid, or thelike. However, other liquids may also be dispensed.

The various liquids may be used, for example, in the liquid deliverysystems 300A-300C. In some embodiments, such as shown in FIG. 3A, themulti-chamber pump 200 may dispense a first liquid (e.g., a reagent, aliquid detergent or wash liquid) from the first liquid source 318 in afirst flow controllable passage 329 to a vessel comprising thedispensing and/or aspirating device 325, and a second liquid (e.g.,water) from the second liquid source 319 in a second flow controllablepassage 341 to the vessel. The vessel may be used to wash and/or cleanone or more probes, for example. In particular, the liquids from thefirst liquid source 318 and the second liquid source are generallydesired to be dispensed at different volume flow rates. In otherembodiments, the first liquid from the first liquid source 318 in afirst flow controllable passage 329 and a second liquid from the secondliquid source 319 may be both provided to a vessel comprising thedispensing and/or aspirating device 325. Another pump (not shown) maythen dispense the mixture of the first liquid and second liquid from thedispensing and/or aspirating device 325 to another location. Forexample, a volume output from the first chamber outlet 242O may be V1,and a volume output from the second chamber outlet 246O may be V2, andV2>V1. In other embodiments, V2>3V1, V2>5V1, or even V2>8V1 in someembodiments.

In some embodiments, a liquid (e.g., purified water) may be used todilute fluid samples, prepare reagents (e.g., where the purified wateris added to a solid or powdered reagent material), used as a liquidbacking to dispense and/or aspirate liquid reagents (e.g., concentratedreagents), used as a liquid backing to aspirate or dispense biologicalfluid specimens, and/or to wash sample containers. For example, thepurified water may be purified to a level that is suitable to be usedfor aspiration and/or dispensing in the testing of analytes or othersubstances in a bio-fluid (blood, plasma and/or serum, urine,interstitial fluid, spinal fluid, cerebral fluid, etc.). For example, apurity of the purified water may be sufficient to meet the standards forASTM/NCCLS Type 1-IV and/or Type A-C, for example. Preferably,ASTM/NCCLS Type 1 and Type A purity standards may be provided.

In another depicted embodiment, the liquid delivery system 300B includesa probe fluidly coupled to the multi-chamber pump 200 that functions asthe dispensing and/or aspirating device 325. In particular, themulti-chamber pump 200 may both aspirate and dispense a liquid (e.g., abiological fluid sample or liquid reagent) by using the first liquidsource 318 as a backing liquid to accomplish low volume aspiration anddispensing, by using the first chamber 222 of the multi-chamber pump 200to achieve precision at aspirating a relatively small volume of theliquid. Using the liquid as a backing liquid means that none or only asmall amount of the backing liquid from the first liquid source 318 maybe dispensed, but the backing liquid is present in the first flowcontrolled passage 329 to draw in the liquid thorough the probe whenaspirating, and push out the liquid out of the probe 325 whendispensing.

The second liquid from the second liquid source 319 may be a wash liquidor purified water that is provided in a second flow controllable passage341 to the probe 325 at a relatively higher volume V2>V1, V2>3V1,V2>5V1, or even V2>8V1. In the depicted embodiment, the flow control ofthe liquid aspiration and/or dispensing from the flow controllablepassages 329, 341 is accomplished by control of one or more valves 323and operation of the multi-chamber pump apparatus 200 by suitablecontrol signals from the controller 327.

In another depicted embodiment, the liquid delivery system 300C includesa probe fluidly coupled to the multi-chamber pump 200 that functions asthe dispensing and/or aspirating device 325. In particular, themulti-chamber pump 200 may both aspirate and dispense a liquid (e.g., abiological fluid sample or liquid reagent) by using the first liquidfrom the first liquid source 318 as a backing liquid to accomplishprecise aspiration and dispensing. This is done by using the firstchamber 222 of the multi-chamber pump 200 to achieve precision ataspirating a relatively small volume of the liquid, such as less thanabout 100 μL. The system 300C may also dispense the first liquid (e.g.,purified water) from the first liquid source 318 by using the secondchamber 224 of the multi-chamber pump 200 to achieve precision ataspirating a relatively larger volume of the first liquid, such as avolume greater than about 200 μL, greater than about 500 μL, greaterthan about 1000 μL, greater than 5000 μL, or even 9000 μL or more insome embodiments. In the depicted embodiment, the flow control of theliquid aspiration and/or dispensing is accomplished by control of one ormore control valves 323 and operation of the multi-chamber pumpapparatus 200 by suitable control signals from the controller 327. Forexample, when dispensing the first liquid at the relatively lowervolume, the flow controllable passage 339 is opened, while the flowcontrollable passage 341 is closed. Similarly, when dispensing at therelatively large volume, the flow controllable passage 341 is opened,while the flow controllable passage 329 is closed.

Accordingly, in each of the preceding embodiments, precise aspiratingand/or dispensing may be achieved at both relatively high volume andrelatively low volume, because the respective first and second chambers222, 224 may be appropriately sized so that each operates at aboveapproximately 25% of its volume dispensing capacity, at aboveapproximately 50% of its volume dispensing capacity, or even aboveapproximately 75% of its volume dispensing capacity in some embodiments.In operation, the multi-chamber pump apparatus 200, in some embodiments,should be able to meter to a volumetric accuracy of at least about +/−5%or less at low volume dispense or aspiration of less than about 100 μL.Likewise, the multi-chamber pump apparatus 200, in some embodiments,should be able to meter to a volumetric accuracy of at least about +/−1%or less at relatively high volume dispense or aspiration of greater thanabout 200 μL, greater than about 500 μL, or even greater than about 1000μL in some embodiment. For example, an accuracy of +/−10.0 μL or less atrelatively high volume dispense and/or aspiration of greater than about1000 μL may be provided.

In one operational method according to embodiments of the invention, theliquid delivery system 300B including the multi-chamber pump apparatus200 is used to aspirate and then dispense a biological liquid. Forexample, in the above-mentioned “chase” or “neat” methods, a robotoperable based upon control signals from a robot controller may positionthe probe 325 into a sample container containing a volume of biologicalliquid (e.g., blood or a blood plasma). The multi-chamber pump 200 maythen draw (aspirate) a small volume of the biological liquid (e.g., lessthan about 100 μL) into the interior channel of the probe 325 from thesample container via appropriate signals from the controller 327, movethe probe 325 via operation of the robot, and transfer (dispense) thesmall amount of the biological liquid into a test vessel (e.g., acuvette). This operation is carried out using the first chamber 222, thefirst flow controllable passage 329, and the first liquid from the firstliquid source 318 as the backing liquid. During the act of dispensing,the second flow controllable passage 341 is close, such that there is noflow therein. Once the relatively low volume dispensing of thebiological liquid is completed, this dispensing may be chased byoperating the multi-chamber pump 200 and dispensing a relatively largervolume of the second liquid 219 through second flow controllable passage341 and out of the probe 325 into the test container. Thus, therelatively larger volume of liquid may be dispensed with excellentaccuracy. The probe 325 and first chamber 222 may also be used toaspirate and dispense liquid reagent from a reagent container as neededfor the testing operation. The system 300C may also be used for carryingout the “chase” and/or “neat” method.

According to another aspect, a liquid delivery method according to someembodiments will now be described with reference to FIG. 4. The liquiddelivery method 400 includes, in 402, providing, in 404, at least oneliquid source containing a liquid, providing a multi-chamber pumpapparatus fluidly coupled to the at least one liquid source, themulti-chamber pump apparatus having a pump body with a first chamber anda second chamber, a piston having a first piston portion of a first pumparea A1 received in the first chamber, and a second piston portion of asecond pumping area A2 received in the second chamber, providing, in406, a dispensing and/or aspirating device fluidly coupled to a firstchamber outlet of the first chamber, and a second chamber outlet of thesecond chamber, and translating the piston to pump liquid to thedispensing and/or aspirating device in 408.

While the invention is susceptible to various modifications andalternative forms, specific system and apparatus embodiments and methodsthereof have been shown by way of example in the drawings and aredescribed in detail herein. It should be understood, however, that it isnot intended to limit the invention to the particular systems,apparatus, or methods disclosed, but, to the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe scope of the invention.

What is claimed is:
 1. A multi-chamber pump apparatus, comprising: apump body containing a first chamber and a second chamber, each adaptedto contain a liquid; a piston having a first piston portion of a firstpump area A1 received in the first chamber, and a second piston portionof a second pumping area A2 received in the second chamber; and anactuator coupled to the piston.
 2. The multi-chamber pump apparatus ofclaim 1, comprising A2>A1.
 3. The multi-chamber pump apparatus of claim1, comprising A2≧3A1.
 4. The multi-chamber pump apparatus of claim 1,comprising A2≧5A1.
 5. The multi-chamber pump apparatus of claim 1,comprising a coupling attaching the piston to a shaft of the actuator.6. The multi-chamber pump apparatus of claim 5, comprising a sensormounted to the pump body and a flag extending from the coupling whereinthe flag is configured to interact with the sensor to provideinformation concerning a position of the piston.
 7. The multi-chamberpump apparatus of claim 5, wherein the pump body comprises: a lowerhousing coupled to the actuator, the lower housing receiving thecoupling and a shaft of the actuator.
 8. The multi-chamber pumpapparatus of claim 1, wherein the pump body comprises: a lower housingcoupled to the actuator; a middle housing coupled to the lower housing,the middle housing containing the first chamber and a first chamberinlet and a first chamber outlet; and an upper housing coupled to themiddle housing, the upper housing containing the second chamber and asecond chamber inlet and a second chamber outlet.
 9. The multi-chamberpump apparatus of claim 8, wherein the middle housing and the upperhousing comprise a transparent material.
 10. The multi-chamber pumpapparatus of claim 1, wherein the piston comprises co-axial cylinders,and the first piston portion of has a diameter D1, and the second pistonportion has a diameter D2, and D1>D2.
 11. A liquid delivery system,comprising: at least one liquid source; a multi-chamber pump apparatusfluidly coupled to the at least one liquid source, the multi-chamberpump apparatus having a pump body with a first chamber and a secondchamber, a piston having a first piston portion of a first pump area A1received in the first chamber, and a second piston portion of a secondpumping area A2 received in the second chamber; a dispensing and/oraspirating device fluidly coupled to a first chamber outlet of the firstchamber, and a second chamber outlet of the second chamber; a firstflow-controllable passage fluidly coupled to the first chamber; and asecond flow-controllable passage fluidly coupled to the second chamber.12. The liquid delivery system of claim 11, comprising: the firstflow-controllable passage fluidly coupled between the first chamberoutlet and the dispensing and/or aspirating device; and the secondflow-controllable passage fluidly coupled between the second chamberoutlet and the dispensing and/or aspirating device.
 13. The liquiddelivery system of claim 11, wherein the dispensing and/or aspiratingdevice comprises a probe receptacle.
 14. The liquid delivery system ofclaim 11, wherein the dispensing and/or aspirating device comprises aprobe.
 15. A liquid delivery method, comprising: providing at least oneliquid source containing a liquid; providing a multi-chamber pumpapparatus fluidly coupled to the at least one liquid source, themulti-chamber pump apparatus having a pump body with a first chamber anda second chamber, a piston having a first piston portion of a first pumparea A1 received in the first chamber, and a second piston portion of asecond pumping area A2 received in the second chamber; providing adispensing and/or aspirating device fluidly coupled to a first chamberoutlet of the first chamber, and a second chamber outlet of the secondchamber; and translating the piston to pump liquid to the dispensingand/or aspirating device.
 16. The method of claim 15, comprising:controlling flow in both a first flow-controllable passage fluidlycoupled between the first chamber outlet and the dispensing and/oraspirating device and a second flow-controllable passage fluidly coupledbetween the second chamber outlet and the dispensing and/or aspiratingdevice.
 17. The method of claim 16, comprising: the firstflow-controllable passage and the second flow controllable passage aresimultaneously open.
 18. The method of claim 16, comprising: one or thefirst flow-controllable passage and the second flow controllable passageis open and one of the first flow-controllable passage and the secondflow controllable passage is closed.
 19. The method of claim 15,comprising: providing a first liquid source coupled to a first chamberinlet of the first chamber, and providing a second liquid source fluidlycoupled to a second chamber inlet of the second chamber.
 20. The methodof claim 19, comprising: dispensing a first liquid from the first liquidsource from the first chamber outlet of the first chamber; anddispensing a second liquid from the second liquid source from a secondchamber outlet of the second chamber.
 21. The method of claim 20,comprising: the dispensing of the first liquid and the dispensing of thesecond liquid occur simultaneously.